Scientists call ‘Code Blue emergency’ for Australian oceans, as off-the-scale marine heat looms

 

OCEAN
IMAGE: AdobeStock_207088658

Climate Council, media release, 9 November 2023:

Scientists call ‘Code Blue emergency’ for Aussie oceans, as off-the-scale marine heat looms

AUSTRALIA’S OCEANS ARE in crisis, as extreme heat punishes marine life and raises the spectre of irreversible changes with profound consequences for all life on our planet, a new report has found.

The Climate Council’s CodeBlue: Oceans in Crisis report reveals the immense amount of climate-change induced heat currently being absorbed by the world’s oceans is equivalent to boiling the Sydney Harbour every eight minutes.

In addition, the Climate Council ran a highly targeted survey of 30 leading ocean scientists across five continents. All (100%) were ‘extremely’ or ‘very’ concerned about climate-driven changes to the world’s oceans. Half (53%) said these changes were outpacing scientific predictions.

Overwhelmingly, these scientists agreed ‘rapidly phasing out fossil fuels’ is the single most important action governments could take to address ocean warming.

Report author and the Climate Council’s Research Director Dr Simon Bradshaw said: "The science can’t be any clearer: our oceans are in deep trouble. Today the ocean is absorbing excess heat energy that’s equivalent to five Hiroshima bomb explosions every second, or enough to boil Sydney Harbour every eight minutes. [my yellow highlighting]

"As our climate changes, driven by rampant burning of coal, oil and gas, our seas are transforming before our eyes. More frequent and severe marine heatwaves are pushing coral reefs to the brink, ice sheets are melting at an alarming rate, ocean currents are slowing and seas are rising. The climate crisis is also an ocean crisis.

"In hospital emergency rooms, a code blue is called when a very serious life-threatening event is underway. We are calling a code blue for our oceans today, because this threatens all the species that inhabit them, the people who depend on them, as well as all life on land.

"Over the past few decades as the climate has warmed, the oceans have done an incredible job of protecting us by absorbing CO2 and an immense amount of heat, but there’s a limit to what they can take and we are close to crossing dangerous tipping points. We must scale up the use of clean energy like solar and wind, backed by storage, as quickly as we can so the use of coal, oil and gas is phased out. Every step that cuts pollution will help secure our future."

Ocean scientist Professor Gretta Pecl, Director for the Centre for Marine Socioecology at the University of Tasmania, author of the Australian ocean section of the latest IPCC report and report co-author added: “Make no mistake, ocean scientists around the world are growing increasingly concerned about rapid and intensifying changes to our oceans.

"While much of the worry for the brutal summer ahead is quite rightly about the impact on our iconic Great Barrier Reef, the scientific community is also extremely concerned about the Great Southern Reef. With forecasts of unprecedented and 'off the charts' marine heat this summer, these critical marine ecosystems face risk of utter devastation.

"We’re observing the transformation of the oceans in real time, as marine species move to survive. In Australia, at least 200 marine species have shifted since 2003, with the vast majority headed south. As waters warm further south, many will have nowhere left to go.

"While climate change has already caused extensive change to our oceans - and we’ll continue to see devastating impacts for decades - stronger action by governments to reign in fossil fuels right now can limit future harms and ensure more species and ecosystems are given a fighting chance. Scientists agree: the single most important action we can take now is to leave fossil fuels in the polluting past - and it has to happen this decade."

Pro-surfer Adrian ‘Ace’ Buchan, Surfing Australia Deputy Chairman, has joined the Climate Council’s call to declare a Code Blue emergency, adding: “Surfers have a deep and spiritual connection to the ocean and we are deeply concerned about the devastating impact the climate crisis is having on our big blue playground. Erosion is threatening our most iconic surfing spots. Our water is being polluted from flood runoff and dangerous jellyfish moving south. Loss of coral reefs and impacts on sandbars, is not just altering where and how waves break, but is also having devastating impacts on marine life.

"This is all terrible news for the millions of ocean loving Aussies - every one of whom should be concerned and take note. This is a call to action: we must work to draw attention to the ocean’s plight and push for decisive and rapid climate action now."

Tishiko King, a proud Kulkalaig woman from Masig in Zenadth Kes (Torres Strait Islands) marine scientist and co-author of the report said: “We know what is needed to protect our futures: leaving fossil fuels in the ground, having the resources to adapt to our changing climate and ocean, being able to access funds to address loss and damage.

"We have the opportunity to work together: First Nations, Pacific Island nations, non-Indigenous Australians. It starts by listening, and understanding what we all have in common. The ocean is what connects us all together."

ENDS

The Climate Council is Australia’s leading community-funded climate change communications organisation. It was founded through community donations in 2013, immediately after the then-Abbott Government dismantled the Climate Commission. We provide authoritative, expert and evidence-based advice on climate change to journalists, policymakers, and the wider Australian community. For further information, go to: climatecouncil.org.au Or follow us on social media: facebook.com/climatecouncil and twitter.com/climatecouncil

Full report can be found at:

https://www.climatecouncil.org.au/resources/code-blue-our-oceans-in-crisis/

Global ocean heat is intensifying and seas below the 30th Parallel South appear to have seen the largest increase in absorbed & accumulated heat

 

‘The world ocean, in 2023, is now the hottest ever recorded, and sea levels are rising because heat causes water to expand and ice to melt,’...‘Ecosystems are also experiencing unprecedented heat stress, and the frequency and intensity of extreme weather events are changing rapidly, and the costs are enormous.’ [Scientia Professor Matthew England, co-author of the study from the UNSW Centre for Marine Science and Innovation, in the Echo, 6 November 2023]

Over the years science has made the general public increasingly aware that anthropomorphic global warming and subsequent climate change has been heating the world's oceans beyond their normal temperature range.

What we aren't always aware of is exactly which oceans are exhibiting the most persistent warming and the fastest temperature rises.

This recent study below highlights those particular oceans.

It seems that ocean waters from the 30th Parallel south (latitude: -30° 00' 0.00" S longitude: 0° 00' 0.00") are experiencing the most rapid increase in temperatures.

To place that in perspective. From a line running through Australian waters from a point roughly halfway between Red Rock on the Clarence Coast and Corindi Beach on the Coffs Coast (NSW), right down to Tasmania and on towards Antarctica, seawater is heating and expanding until at latest measurement the reading over time now stands at 75.3 ± 4.

While from around Cape Leeuwin to Antarctica the reading is 43.2 ± 4.4.

On the Australian west coast the 30th Parallel can be thought of as running on a latitude approximately halfway between Leeman and Green Head (WA).

This study appears to indicate that, sooner rather than later, the considerable impacts of climate change will increase for the Australian population.

Nature Communications, Article number: 6888 (2023), 28 October 2023, excerpts:

Recentacceleration in global ocean heat accumulation by mode andintermediate waters

Authors: Zhi Li, Matthew H. England & Sjoerd Groeskamp

The ocean directly impacts the Earth’s climate by absorbing and redistributing large amounts of heat, freshwater, and carbon, and by exchanging these properties with the atmosphere1. About 91% of the excess heat trapped by greenhouse gases and 31% of human emissions of carbon dioxide2 are stored in the ocean, shielding humans from even more rapid changes in climate. However, warmer oceans result in sea-level rise, ice-shelf melt, intensified storms, tropical cyclones, and marine heatwaves, as well as more severe marine species and ecosystem damage. These effects depend on the pattern of ocean warming; it is thus critical to quantify the dynamics and distribution of ocean warming to better understand its consequences and predict its implications.

The observed distribution of ocean warming is not uniform. About 90% of total ocean warming is found in the upper 2000 m, with over two-thirds concentrated in the upper 700 since the 1950s, and an increase of warming rates at both intermediate depths of 700–2000 m, and in the deeper ocean below 2000 m. The Southern Ocean south of 30°S has been estimated to account for 35–43% of global ocean warming from 1970 to 2017, and an even greater proportion in recent years, while Northern Hemisphere ocean warming appears to be concentrated in the Atlantic Ocean. Due to the accumulated excess heat in ocean basins, an acceleration of total ocean warming has become more evident from recent observational-based studies. While much past work has focused on the distribution of ocean warming as a function of depth and basin, relatively little analysis has been undertaken of the distribution as a function of water-mass layers and within specific water masses. This is the focus of the present study......

When evaluating the ocean heat uptake for each decade (“Methods”), analysis of the past three decades reveals that the ocean heat uptake during 2010–2020 has increased more than 25% relative to 2000–2010 and has nearly doubled relative to the 1990’s WOCE era, as seen in Fig. 1b, where we highlight the decadal ocean heat uptake since the 1960s. Note that there has been both increased ocean sampling and a shift of the observational network from a ship-based system to the Argo network since the initiation of the global Argo array (2001–2003)34. This may impact the estimated increase in global ocean warming over the past three decades (Fig. 1). However, the rate of global mean sea-level rise has also been increasing since 1993 based on an independent estimate from satellite altimeter data1,35, providing confidence in our results given that half of the global sea surface height increase is due to thermal expansion of the ocean since altimeter measurements began. Significant ocean warming and accelerating OHC changes are also consistent with the increase in net radiative energy absorbed by Earth detected in satellite observations, something that is likely to continue throughout the 21st century in the absence of substantial greenhouse gas emissions reductions.

The increased ocean warming is non-uniformly distributed across ocean basins. Overall, in each ocean basin, an increase in OHC is observed (values indicated in Fig. 2a, b), with stronger warming in the mid-latitude Atlantic Ocean and the Southern Ocean compared with other basins. Total warming in the Southern Ocean is estimated to account for ~31% of the global upper 2000-m OHC increase from 1980–2000 to 2000–2010 (Fig. 2a), and almost half of the global OHC increase from 2000–2010 to 2010–2020 (values indicated in parentheses of Fig. 2b). Hence the Southern Ocean has seen the largest increase in heat storage over the past two decades, holding almost the same excess anthropogenic heat as the Atlantic, Pacific, and Indian Oceans north of 30°S combined (Fig. 2d). The most striking warming in the Southern Ocean is concentrated on the northern flank of the Antarctic Circumpolar Current, the location of deep mixed layers and subduction hotspots for Subantarctic Mode Water and Antarctic Intermediate Water, as well as the location of subtropical mode waters formation further equatorward (Fig. 3). The well-ventilated regions near western boundary current extensions in the North Atlantic and North Pacific also reveal large warming over the past two decades. These hotspots of ocean warming are likely linked to enhanced uptake, subduction, and lateral spreading of heat associated with mode and intermediate waters that warrant further investigation.

Fig. 2: Regional intensification in ocean warming over the past two decades, 0–2000 m. Click on image to enlarge

The ensemble mean of ocean heat content (OHC) changes averaged for years a 2000–2010 and b 2010–2020, relative to the 1980–2000 mean. Units of shadings in panels (a, b) are shown as 109 J m−2. The values over each basin indicate the OHC increase relative to the 1980–2000 mean over the Southern (S.O., south of 30°S, dark-red line), Atlantic (ATL), Pacific (PAC), and Indian (IND) Oceans, and are limited to 65°S–65°N. Units are shown as 1021. The values in parentheses in panel (b) indicate the basin-integrated OHC increase from 2000–2010 to 2010–2020. The basin mask used to distinguish ocean basins of the Southern, Atlantic, Pacific, and Indian Oceans is obtained from ref.  Superimposed gray contours represent the positions of wintertime isopycnals 25, 26.45, 27.05, and 27.5 kg m−3 at 10 m depth from SIO RG-Argo. c, d Zonally integrated OHC change (1021 per degree latitude) versus latitude for the period 2000–2010 (blue line), and 2010–2020 (red line), relative to the 1980–2000 mean. Lines in panels (c) and (d) represent the ensemble mean, and shadings indicate the ±2 ensemble standard deviation uncertainty range (±2σ) of OHC changes.

[my yellow highlighting in the excerpts]

The full study can be read and downloaded at:

https://www.nature.com/articles/s41467-023-42468-z#ref-CR13

Cartoons of the Week

 

Winner of the Climate Cartoon People’s Choice Award

 2023

Cathy Wilcox
1 November 2023



Runners Up

Andrew Weldon

Megan Herbert

Tweed Shire expects to start rolling out water restrictions within next few weeks and rest of the Northern Rivers region likely to be following its lead sooner rather than later

NSWDPI Combined Drought Indicator (CDI) mapping, 23 September 2023. CDI = Combined Drought Indicator. RI = Rainfall Index. SWI = Soil Water Index. PGI = Pasture Growth Index. DDI = Drought Direction Index

Click on map to enlarge

There are 19 large dams on NSW regional regulated rivers and hundreds of smaller dams, reservoirs & weirs associated with a mix of environmental use, off-farm agricultural and urban water storage on other rivers.

Across the seven local government areas in the Northern Rivers region water storage locations include:

Toonumbar Dam

Rocky Creek Dam

Clarrie Hall Dam

Emmigrant Creek Dam

Korrumbyn Creek Dam

Shannon Creek Dam

Bray Park weir

Tyalgum weir

Mullumbimby Power Station weir

Jambour weir

Kyogle weir

Nymboida weir

Rushforth Road 100ML Reservoir.

Tweed Shire Council is strongly alerting its residents and ratepayers as to the current situation and what may lie ahead.

The Echo, 27 September 2023:

Following the devastating floods of 2022 we are back to dry weather. The Bureau of Meteorology (BOM) has declared an El Nino weather pattern and it has predicted that there will be less-than-average rainfall in the Northern Rivers this year. Tweed Council is reminding residents and visitors that it is important to save water as we head into dry weather.

‘Without significant rain, the Tweed will head into water restrictions, with restrictions for Tyalgum looking likely in the next few weeks,’ said Tweed Shire Council’s (TSC) water and wastewater business and assets manager Michael Wraight.

‘We source our water from the Tweed River at Bray Park and Uki, plus the Oxley River at Tyalgum. The river flows are down and the weir pools at Bray Park and Tyalgum are drying up.

‘While Clarrie Hall Dam is currently sitting at 98 per cent capacity, it will now drop about 1 to 1.5 per cent, per week, as we start releasing water to supply the Bray Park Weir – the source of water for most of the Shire.

‘We will trigger level 1 water restrictions when the Clarrie Hall Dam level drops to 85 per cent.

‘Restrictions at Tyalgum will be introduced sooner. The flow of the Oxley River at Tyalgum is down to a trickle and the weir pool there is dropping fast.’

The other shoe has finally dropped - El Niño has been declared by Australian Bureau of Meteorology

Click on image to enlarge

Central and eastern Pacific sea surface temperatures (SSTs) currently exceed El Niño thresholds. International climate models suggest some further warming of the central and eastern tropical Pacific Ocean is likely. All surveyed models indicate SSTs will remain above El Niño thresholds until at least the end of the 2023–24 southern hemisphere summer.

Bureau long-range forecasts are for SSTs up to 2.5 °C warmer than average off eastern Tasmania and in the eastern Tasman Sea from October to the end of 2023.

Click on image to enlarge

Australian Bureau of Meteorology, 19 September 2023:

ElNiño and positive Indian Ocean Dipole underway

An El Niño and a positive IOD are underway.

The declaration of these events, and their concurrence over spring, reinforces the Bureau's long-range rainfall and temperature forecasts, which continue to predict warmer and drier conditions for much of Australia over the next three months. The confirmation of an established El Niño increases the likelihood that the event will be sustained through the summer period.

Oceanic indicators firmly exhibit an El Niño state. Central and eastern Pacific sea surface temperatures (SSTs) continue to exceed El Niño thresholds. Models indicate further warming of the central to eastern Pacific is likely.

Broadscale pressure patterns over the tropical Pacific reflect El Niño, with the 90-day Southern Oscillation Index (SOI) at −7.7. Recent trade wind strength has been generally close to average, but was slightly weaker than average across the tropical Pacific in August 2023 for the first time since January 2020.

Overall, there are signs that the atmosphere is responding to the pattern of SSTs in the tropical Pacific and coupling of the ocean and atmosphere has started to occur. This coupling is a characteristic of an El Niño event and is what strengthens and sustains an event for an extended period. Climate models indicate this El Niño is likely to persist until at least the end of February. El Niño typically leads to reduced spring and early summer rainfall for eastern Australia, and warmer days for the southern two-thirds of the country.

A positive Indian Ocean Dipole is underway. The Indian Ocean Dipole (IOD) index is +1.25 °C for week ending 17 September. This is its fifth week above the positive IOD threshold (+0.40 °C). The longevity of this trend, combined with the strength of the dipole being observed and forecast, indicate a positive IOD event is underway. All models predict this positive IOD will persist to at least the end of spring. A positive IOD typically leads to reduced spring rainfall for central and south-east Australia.

When a positive IOD and El Niño occur together, their drying effect is typically stronger and more widespread across Australia.

The Madden–Julian Oscillation (MJO) is currently weak and is forecast to remain weak over the coming week.

The Southern Annular Mode (SAM) index is currently negative and is expected to remain negative for at least the coming week, before a possible return to neutral late in September. During spring, a negative SAM is associated with decreased rainfall across parts of the east in both NSW and Victoria, and increased rainfall over western Tasmania.

The long-rangeforecast for Australia indicates warmer and drier than average conditions are likely across most of southern and eastern Australia from October to December. The Bureau's climate model takes into account all influences from the oceans and atmosphere when generating its long-range forecasts.

Global warming

Global warming continues to influence Australian and global climate. Global sea surface temperatures (SSTs) were warmest on record for their respective months during April to August 2023. August 2023 SSTs were also the warmest globally for any month since observational records began in 1850. July and August 2023 were also respectively the hottest and second-hottest months globally in terms of 2-metre air temperature.

Australia’s climate has warmed by an average of 1.48 ± 0.23 °C since national records began in 1910. There has also been a trend towards a greater proportion of rainfall from high intensity, short duration rainfall events, especially across northern Australia. Southern Australia has seen a reduction, by 10 to 20%, in cool season (April to October) rainfall in recent decades. This is due to a combination of natural variability on decadal timescales and changes in large-scale circulation caused by an increase in greenhouse gas emissions.

^^^^^^^^^^^^^^^^^^^^

Australia and the world are fast running out of time to limit negative impacts of climate change to spans of multiple generations rather than millennia

 

The United Nations website is very clear about what has been agreed at an international level concerning the global response required to limit the Earth’s global warming to an average 1.5°C, thereby limiting the negative impacts of climate change in intensity and time span – hopefully to spans of multiple generations rather than millennia.

The Paris Agreement is a legally binding international treaty on climate change. It was adopted by 196 Parties at the UN Climate Change Conference (COP21) in Paris, France, on 12 December 2015. It entered into force on 4 November 2016.

Its overarching goal is to hold “the increase in the global average temperature to well below 2°C above pre-industrial levels” and pursue efforts “to limit the temperature increase to 1.5°C above pre-industrial levels.”

Australia is a party to the 2015 Paris Agreement, effective 4 November 2016.

However, in recent years, world leaders have stressed the need to limit global warming to 1.5°C by the end of this century.

That’s because the UN’s Intergovernmental Panel on Climate Change indicates that crossing the 1.5°C threshold risks unleashing far more severe climate change impacts, including more frequent and severe droughts, heatwaves and rainfall.

To limit global warming to 1.5°C, greenhouse gas emissions must peak before 2025 at the latest and decline 43% by 2030.

All those nations which entered into the Paris Agreement agreed to participate in the global attempt to reduce the world’s greenhouse gas emission by establishing firm undertakings in Nationally Determined Contributions (NDCs).

In their NDCs, countries communicate actions they will take to reduce their greenhouse gas emissions in order to reach the goals of the Paris Agreement. Countries also communicate in their NDCs actions they will take to build resilience to adapt to the impacts of climate change.

Australia submitted its first NDC to the United Nations Framework Convention on Climate Change (UNFCC) in 2015 and updated that version of the NDC in 2022. This update commits Australia to reducing its emissions to 43% below 2005 levels by 2030. It should be noted that in 2005 Australia’s total national greenhouse gas emissions of 559.1 million tonnes of carbon equivalent gases (MT CO²-e) was already 102.2% of its 1990 annual total of 515.9 MT CO²-e.

It could be said that even now our national reduction of greenhouse gas emissions is sluggish at best.

"For the year to June [2023], according to the preliminary numbers from the government’s latest national greenhouse gas inventory, emissions were 4.1 million tonnes above those for the corresponding period the previous year." [The Saturday Paper, 08.09.23]

 

In the year to December 2015 Australia’s “annual unadjusted” greenhouse gas emissions stood at 529.2 MT CO²-e. An artificially constructed figure because per government policy it excluded emissions from from land use, land use change and forestry. These excluded emissions would have possibly added more than 1.0 MT CO²-e bringing the national annual total to over 30 MT CO²-e in 2015.

By year to December 2022 Australia’s “actual annual” greenhouse gas emissions were recorded as 463.9 MT CO²-e. A figure arrived at by an alleged fall in emissions from land use, land use change and forestry of est. -13.6 MT CO²-e due to professed reductions in land clearing and native forest harvesting, increases in plantations and native vegetation, and improvements in soil carbon. NOTE: By year to December 2022 each person in Australia was estimated to be responsible for 17.8 tonnes CO²-e of that year’s greenhouse gas emissions total.

What Australian governments and industries has effected was a paltry national greenhouse gas emissions change of est.

-65.3 MT CO²-e spread over eight years – an average of 8.1. Or est. -95.2 MT CO²-e spread over 17 years – an average of 5.6 MT CO²-e per annum. And that change was to a significant degree on the back of the adoption of rooftop renewable energy by the general population which in the year to December 2022 was contributing to an electricity sector emissions reduction of 5.5 MT CO²-e, according to the Dept. of Climate Change, Energy, the Environment and Water.

Either way, leaving Australia with an urgent need to reduce greenhouse gas emissions by at least the promised -240.4 MT CO²-e within the next seven years. That’s roughly 34.3 MT CO²-e emissions we have to cease releasing into the air, waterways and oceans each and every year until 2030 to even have a chance at surviving as a nation and a functioning society beyond that year.

Creative accounting using offsets, hiding behind green washing propaganda, pushing hard decisions further down the track into the future, just won’t work. We need to immediately tighten polluting emissions regulations & abatement requirements, begin phasing out current unabated fossils greenhouse gas and, from this point in time where we stand right now, we must refuse all new or expanded proposals for fossil fuel extraction and use.

Australian industry and corporations both foreign and domestic are laughing in our faces and, federal & state governments appear all but frozen into inaction by the magnitude of the climate crisis before us. There will be no heroes coming down from the mountains to save us, no ships arriving to sail us all to as yet undiscovered safety, no divine miracles falling from the skies.

Australia’s estimated resident population stood at 26,268,359 men, women and children in December 2022 according to the Australian Bureau of Statistics. 

An estimated 21,461,249 of the resident population in 2022 were individuals 15 years of age and older.

By default theirs is the burden of stopping that 240.4 MT CO²-e of additional pollution entering earth’s atmosphere over Australia by 2030. That’s an extra 11.2 tonnes CO²-e per person averaging 1.6 tonne of carbon equivalent a year.

So how do we each attempt to shoulder this terrible burden? 

"Key finding 4: global emissions are not in line with modelled global mitigation pathways consistent with the temperature goal of the Paris Agreement, and there is a rapidly narrowing window to raise ambition and implement existing commitments in order to limit warming to 1.5 °C above pre-industrial levels." 

[United Nations Framework Convention on Climate Change (FCCC), Technical dialogue of the first global stocktake, Advance Version 8 September 2023, excerpt]

 

PRINCIPAL SOURCES

• UN., Climate Change, retrieved 8 September 2023
• U.N., The Paris Agreement
• U.N., Technical dialogue of the first global stocktake. Synthesis report by the co-facilitators on the technical dialogue, Advance Version 8 September 2023
• U.N., Nationally Determined Contributions Registry
• DCCEEW, Australia’s National Greenhouse Accounts, 1990 onwards
• DCCEEW, National Inventory Reports
• DCCEEW, National Greenhouse Gas Inventory: Quarterly updates 2009-2023
• ABS, Australia's Environment: Issues and Trends, 2002 onwards
• ABS, Year Book Australia, 2005
• Our Word In Data, C02 Emissions
• Nature, Food, Global food-miles account for nearly 20% of total food-systems emissions, 15 December 2022

Postscript:

Stocktaking our personal emissions level and, looking at ways of reducing that average per head of population average green house gas emission excessive budget of 17.8 tonnes CO²-e, may be something we can all attempt. 

For example: 

• the average vehicle in Australia is estimated to travel 12,100 km per year or 33.2 km per day, which represents around 2.1 tonne CO²-e annually; 

• while the average household across all power supply types is estimated to consume 5,818.6kw/h of electricity each year, which can be as high as 3 tonne CO²-e annually depending on the mix of supply types per household; and

• imported food or imported ingredients have food transport kilometres attached, which in Australia's case means food importation from the European Union represents est. 1.3 MT CO²-e annually or approx. 50 kg CO²-e per capita. A serve of deli sausage from Denmark travels est. 25,000 food kilometres to reach the supermarket counter. 

Time to get cracking and shame the devils who brought us to this catastrophic pass - even if the task appears impossible and we merely so many cursed children of a condemned Sisyphus.

This next Southern Hemisphere Summer may bring more unwelcome news for Australia's coastal zone

 

“Climate breakdown has begun”

[U.N. Secretary-General Antonio Guterres, 6 September 2023]

NOAA Research, Global ocean roiled by marine heatwaves, with more on the way, 28 June 2023, excerpts:

This map depicts predicted marine heatwave conditions in September 2023 as generated by the Physical Sciences Laboratory’s experimental forecast model.

Credit: NOAA Physical Sciences Laboratory. *Click on image to enlarge*

The experimental forecast, which tracks the NOAA Climate Prediction Center’s official outlook, is based on a large ensemble of climate model predictions spanning June 2023 through May 2024….

A marine heatwave is defined as a monthly regional sea surface temperature anomaly that ranks in the top 10% of warmest months compared with the 1991–2020 average. Long-term ocean warming trends also contribute to unusually high ocean temperatures, but even with the effects of long-term warming removed, models predict 25% of the global ocean will experience sharp upward departures from more recent conditions by September…..

In this scenario it appears that the Southern Ocean waters are within a probability range of between 60-80 per cent for the occurrence of marine heatwave which might have also lead to a rise in Antarctic sea surface temperatures.

Which begs the questions:

How will the over 60km long Halloween Crack in west Antarctica react to any additional stressors on the Brunt Ice Shelf?

Will the East Coast Ice Sheet which is said to contain four fifths of the world’s ice again lose ice shelf through iceberg calving as it did with C-37 (144 sq.km) & C-38 (415 sq. km) in March 2022?

Just how big are these Anthropocene Age icebergs going to grow – given many are the size of cities already? and

How long does the Southern Hemisphere have before sea level rise beyond the Antarctic Circle increases exponentially past millimetres into metres?

BACKGROUND

NASA Earth Observatory, retrieved from website 7 September 2023:

Antarctica’sBrunt Ice Shelf Finally Breaks

January 24, 2023

In February 2019, a rift spanning most of the Brunt Ice Shelf in Antarctica appeared ready to spawn an iceberg about twice the size of New York City. The question among scientists was not if the growing rift would finish traversing the shelf and break, but when? Now, nearly four years later, it has done just that.

According to the British Antarctic Survey (BAS), the break occurred late on January 22, 2023, and produced a new iceberg with an area of 1550 square kilometers (about 600 square miles). The U.S. National Ice Center has named it Iceberg A-81. The berg is visible in this image, acquired on January 24, 2023, with the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite.

The glacial ice in the shelf flows away from the interior of Antarctica and floats on the eastern Weddell Sea. (For reference, the Antarctic Peninsula and its ice shelves are located on the opposite side of the Weddell.) The shelf has long been home to the British Antarctic Survey’s Halley Research Station, where scientists study Earth, atmospheric, and space weather processes. BAS reported that the station, which was relocated farther inland in 2016 as the chasm widened, was unaffected by the recent break.

January 12, 2021

The break occurred along a rift known as Chasm 1. This chasm started growing in the 1970s, followed by a period of dormancy, and then resumed growth in 2012. It continued to lengthen for almost a decade, extending by as much as 4 kilometers (2.5 miles) per year in early 2019. But even this growth spurt slowed. That is, until the 2022–2023 Antarctic summer when the chasm sped up and ultimately broke past the McDonald Ice Rumples—a submerged knob of bedrock that served as a pinning point for this part of the shelf. Several factors may have contributed to the completion of the break, including a lack of sea ice to help resist, or “push back,” against the stresses on the shelf ice in 2023.

The second image, acquired with the Operational Land Imager (OLI) on Landsat 8, shows the extent of Chasm 1 on January 12, 2021, about two years prior to the break. Notice several other cracks across the northeast part of the shelf. The “new crack” in that image ultimately separated in February 2021 and formed Iceberg A-74.

“The rapid formation of subsequent rifts—to long-standing Chasm 1 and 2—and recent calving to the northeast makes it clear that these shelf areas are dynamic with poorly understood stresses,” said Christopher Shuman, a University of Maryland, Baltimore County, glaciologist based at NASA’s Goddard Space Flight Center.

The breaking (calving) of icebergs from ice shelves is part of a natural, cyclical process of growth and decay at the limits of Earth’s ice sheets. As glacial ice flows from land and spreads out over the sea, shelf areas farthest from shore grow thinner. These areas are stressed by storms and tides and thin as they are melted from above or below, ultimately making them more prone to forming rifts and breaking away.

As for the “new” Brunt, it remains to be seen how the complex floating glacial ice responds to the most recent calving event. According to Shuman: “We have no solid idea what ‘normal’ really is for this unusual ice shelf.”

NASA Earth Observatory images by Lauren Dauphin, using MODIS data from NASA EOSDIS LANCE and GIBS/Worldview and Landsat data from the U.S. Geological Survey. Story by Kathryn Hansen.

~~~~~~~~~~~~~~~~~

Other large iceberg calvings

NASA Earth Observatory

Early on July 12, 2017, satellites captured imagery of the new, massive iceberg that broke away from Larsen C—an ice shelf on the east side of the Antarctic Peninsula…..On July 13, the U.S. National Ice Center issued a press release confirming the new iceberg and officially naming it A-68.

February 22 - March 21, 2022

Collapse of the ice shelf in front of both the Glenzer Glacier (C-37) and Conger Glacier (C.38)commencing around 12 March 2022.